external image altsalinity.jpg
external image altsalinity.jpg

The definitions of a estuary is when part of fresh water meets salt water and is dumped into the ocean. They are near other biomes such as oceans, freshwater wetland, Taiga, pretty much any biome that has fresh water that leads to an ocean.


The climate of an Estuary can range from 20 to 70 degree Fahrenheit.
This could change the why the body of water interact with one another such as:
  • Highly Stratified - when the marine and rivers intakes are about the same but the rivers flow is still higher, then mixes the salt water to decrease than reverse.
  • Inverse Estuary - there is no input of fresh water and found in location with high evaportation.
  • Vertically Mixed - the marine intake dominates the rivers output, freshwater life dies off leaving salt water animals alone.
  • Intermittent Estuary - depends on the fresh water intake, can change from whole marine to any other of the estuary types.

Vegetation Types & Adaptations

Currents in the estuaries come from tides, river runoff, transport by wind generated surface waves, direct stress by wind on water surface, variations in density distributions, and internal waves. Several terms are used interchangeable with estuary: wetlands, lagoon, slough, salt marsh, marsh, swamp. The term lagoon is the region between a barrier islands or spit and the mainland, a slough is a shallow estuary with large areas of the bottom exposed during low tides, a salt marsh is a shallow tidal estuary protected from ocean waves and inhabited by plants and can withstand submergence. The term marsh (used interchangeable with salt marsh) but in precise sense refers to a region with zero salinity upstream from a salt marsh. A swamp is a lowland area saturated with water often quite large and farther inland. The estuary is a nutrient trap, partly physical and partly biological. Retention and rapid recycling of nutrients by benthos, formation of organic aggregates and detritus, and the recovery of nutrients from deep sediments by microbial activity, and deep plant roots create a self-enriching system.

The estuary is a hostile environment for most plants because salt dominates. A few grow further back on the shore, where they live in a fluctuating environment of seawater and fresh water. These plants must cope with:
• varying salinity levels
• strong currents and storm waves
• varying exposure to sunlight and wind
• low oxygen levels in muddy soils.

Some types of vegetations are:
external image estuaries_18.gif
external image estuaries_18.gif

• Sea grass
• Sea grass Decline
• Mangroves
• Salt marsh plants
• Salt Meadows
• Cordgrass

Habitat alteration such as the filling of marshes and tidal flats, and reconstruction of shorelines to accommodate the needs of development, transportation, and agriculture, can degrade estuaries. Wetland loss and degradation have limited the amount of habitat available to support healthy populations of wildlife and marine organisms. The clearing of land to obtain timber, the construction of homes and roads, and other development projects completed without properly revegetating the area can lead to excessive sediments being washed into the estuarine environment. These sediments muddy the water, preventing sunlight from reaching aquatic vegetation and making the water unappealing to swimmers. Sediments can also carry excess nutrients, pesticides, and toxic substances, causing additional water quality problems.
An estuary is a partially enclosed body of water formed where freshwater from rivers, streams, and groundwater flows to the ocean, mixing with the salty seawater. Although influenced by the winds and tides, estuaries are protected from the full force of ocean waves, winds, and storms by the reefs, barrier islands, or fingers of land, mud, or sand that define an estuary's seaward boundary.


Estuaries are special. They are in areas where freshwater meets and mixes with salty ocean waters. The term estuaries, according to general usage, refer to protected, near shore waters, such as bays and lagoons.

Estuaries are rich in animal life and are often a protected area where organisms seek refuge. There are a lot if these animals that live in estuaries that people like to eat, for example clams, shrimp and lots of fish.

Estuaries are the most productive ecosystems in nature. Rivers and streams drain into estuaries, bringing in nutrients from the upperlands. Plants use these nutrients, along with the sun's energy, carbon dioxide, and water, to manufacture food. During decomposition, detritus becomes smaller and smaller and the nutrients and small particles become food for thousands of organisms. Larger animals feed directly on these tiny particles or on smaller animals that fed on detritus.

As long as nutrient-rich freshwater flows and tides interact without human interference, our estuaries will remain productive. Snook, trout, mullet, jack, grouper, red fish, silver perch, spot, catfish, sheep head, spiny lobster, shrimp, crabs, oysters, and clams are examples of the diverse marine animals dependent upon healthy estuaries. Estuaries also provide breeding and nesting areas, or rookeries, for many coastal birds, including several endangered species, such as brown pelicans. Estuaries' role as the ocean's nurseries cannot be overemphasized.


Estuary ecosystems are influenced by the input of salt water through ocean inlets. Because of this, several animals that feed in this system have adaptations that allow them to tolerate brackish water and saltwater.
Salt glands are what allow many seabirds to maintain themselves on diets of marine prey and seawater, far from any source of freshwater.

Human Impacts/Stresses

Population has grown on the coastal part of the United States greatly every year. From this increase in population comes along with it, human activities which most of the time are misleading. Increases in nutrients, such as eutrophication, occur naturally but because of

human population growth this process now occurs more rapidly. High imputs of nutrients can cause fish disease, toxic and nontoxic algae blooms, low dissolved oxygen, and marked change in plankton and benthic community structure. When exposed to toxicants, such as metals or organic substances, the seafood harvested from the coastal waters can cause severe illness or even death. Coastal population has also increased a big concern for pathogens, like viruses and bacteria, to coastal waters because of citizens dumping garbage and sewage. There are also many human activities that directly affect the habitat of estuarine specie. Conversion of open land and forest for commercial development, agriculture, forestry, highway construction, marinas, and damming are some of the activities that are greatly affecting their habitat. Even with all the mistake’s we make with dumping garbage and other substances into the environment, we are still trying to correct ourselves and make estuaries a better place for many organisms.

Major products/Exports/Goods and Services

Estuaries are among the most productive ecosystems in the world for plant and animal production. They are critical habitats to many species of fish, shellfish, birds and marine mammals. They are nurseries for many species of fish that are harvested in the open sea. Communities living near estuaries around the world depend on them for their food security and livelihoods. Estuaries therefore not only play a critical role in the generation of fish and shellfish, but also form the basis of many local and regional economies.

Estuaries are waste processors. This leads to the very high productivity of plants and animals that is typical of estuaries. The mixing and recycling of organic matter enables estuaries to absorb part of the human wastewater and by products of surrounding cities and towns. Estuaries, and their associated wetlands, serve as storm buffers that absorb wave energy and rising tidal waters during storms. Estuaries are central to commerce and trade in many regions and have traditionally been a place for human settlement. As places of great beauty, estuaries strongly influence the high value of waterfront property and provide for a diversity of economically important recreational activities.

Sources estuary .htm,7305,348196-,00.html